1/*
2 * Copyright 2017 The OpenSSL Project Authors. All Rights Reserved.
3 *
4 * Licensed under the Apache License 2.0 (the "License"). You may not use
5 * this file except in compliance with the License. You can obtain a copy
6 * in the file LICENSE in the source distribution or at
7 * https://www.openssl.org/source/license.html
8 */
9
10#include <stdio.h>
11#include "internal/cryptlib.h"
12#include "dh_local.h"
13#include <openssl/bn.h>
14#include <openssl/objects.h>
15#include "crypto/bn_dh.h"
16
17static DH *dh_param_init(const BIGNUM *p, int32_t nbits)
18{
19 DH *dh = DH_new();
20 if (dh == NULL)
21 return NULL;
22 dh->p = (BIGNUM *)p;
23 dh->g = (BIGNUM *)&_bignum_const_2;
24 dh->length = nbits;
25 dh->dirty_cnt++;
26 return dh;
27}
28
29DH *DH_new_by_nid(int nid)
30{
31 switch (nid) {
32 case NID_ffdhe2048:
33 return dh_param_init(&_bignum_ffdhe2048_p, 225);
34 case NID_ffdhe3072:
35 return dh_param_init(&_bignum_ffdhe3072_p, 275);
36 case NID_ffdhe4096:
37 return dh_param_init(&_bignum_ffdhe4096_p, 325);
38 case NID_ffdhe6144:
39 return dh_param_init(&_bignum_ffdhe6144_p, 375);
40 case NID_ffdhe8192:
41 return dh_param_init(&_bignum_ffdhe8192_p, 400);
42 default:
43 DHerr(DH_F_DH_NEW_BY_NID, DH_R_INVALID_PARAMETER_NID);
44 return NULL;
45 }
46}
47
48int DH_get_nid(const DH *dh)
49{
50 int nid;
51
52 if (BN_get_word(dh->g) != 2)
53 return NID_undef;
54 if (!BN_cmp(dh->p, &_bignum_ffdhe2048_p))
55 nid = NID_ffdhe2048;
56 else if (!BN_cmp(dh->p, &_bignum_ffdhe3072_p))
57 nid = NID_ffdhe3072;
58 else if (!BN_cmp(dh->p, &_bignum_ffdhe4096_p))
59 nid = NID_ffdhe4096;
60 else if (!BN_cmp(dh->p, &_bignum_ffdhe6144_p))
61 nid = NID_ffdhe6144;
62 else if (!BN_cmp(dh->p, &_bignum_ffdhe8192_p))
63 nid = NID_ffdhe8192;
64 else
65 return NID_undef;
66 if (dh->q != NULL) {
67 BIGNUM *q = BN_dup(dh->p);
68
69 /* Check q = p * 2 + 1 we already know q is odd, so just shift right */
70 if (q == NULL || !BN_rshift1(q, q) || !BN_cmp(dh->q, q))
71 nid = NID_undef;
72 BN_free(q);
73 }
74 return nid;
75}
76